现有订单表结构为Orders(id VARCHAR2(64), OrderDate DATE, OrderPrice NUMBER, Customer VARCHAR2(50))，下面哪个语句能正确查找所有订单总金额少于2000的客户？
SELECT Customer,SUM(OrderPrice) FROM Orders GROUP BY Customer HAVING SUM(OrderPrice)<2000;
SELECT t.Customer FROM (SELECT Customer, SUM(OrderPrice) sum FROM Orders) t WHERE t.sum<2000;
SELECT DISTINCT Customer FROM Orders WHERE SUM(OrderPrice)<2000;
SELECT Customer,SUM(OrderPrice) FROM Orders HAVING SUM(OrderPrice)<2000;
